net: macb: add mpfs specific usrio configuration

net: macb: add mpfs specific usrio configuration

On mpfs the driver needs to make sure the tsu clock source is not the
fabric, as this requires that the hardware is in Timer Adjust mode,
which is not compatible with the linux driver trying to control the
hardware. It is unlikely that this will be set, as the peripheral is
reset during probe, but if the resets are not provided in devicetree
it's probable that this bit is set incorrectly, as U-Boot's macb driver
has the same issue with using usrio settings for at91 platforms as the
default.

Fixes: 8aad66aa59be5 ("net: macb: add polarfire soc reset support")
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20260325-excavate-jester-798e7cfe02b5@spud
Signed-off-by: Jakub Kicinski <kuba@kernel.org>